CN116378057A - Foundation pit guard pile construction method - Google Patents

Abstract

The application discloses foundation ditch fender post construction method relates to the field of pile foundation construction technique, and it includes: firstly, constructing a foundation pit guard pile, arranging a pile body of the foundation pit guard pile in a soil body, arranging a pre-pulling hole along the length direction of the pile body, and penetrating a pre-pulling rope in the pre-pulling hole, wherein the lower end of the pre-pulling rope is fixedly arranged with the pile body; step two: the pile body is applied with prestress, the upper end of the pretensioned rope is pulled, and after the pretensioned rope is pulled to a set position, the upper end of the pretensioned rope is fixed to keep the prestress of the pretensioned rope. The pile body bending prevention device has the effect of preventing the pile body of the foundation pit guard pile from bending, enhances the capacity of the pile body for resisting lateral soil pressure, can effectively reduce the deformation of the pile body, and ensures the safety of foundation pit engineering.

Description

Foundation pit guard pile construction method

Technical Field

The application relates to the field of pile foundation construction technology, in particular to a construction method of foundation pit fender piles.

Background

The foundation pit enclosure is a supporting method for developing and utilizing underground space, constructing various underground buildings such as multi-layer basements, underground railways, underground commercial streets and the like. The foundation pit guard piles are pile foundation structures which are pre-buried around the foundation pit to be excavated and used for supporting soil around the foundation pit.

Referring to fig. 1, after the excavation of the foundation pit 1 is completed, the foundation pit guard piles 2 are mainly pressed by one side of the soil body 3, so that the foundation pit guard piles 2 are easy to bend and deform; and bending deformation of the foundation pit guard piles 2 can cause sinking of soil bodies 3 around the foundation pit 1, press structures such as embedded pipelines in the soil bodies 3 and the like, and influence construction quality.

In pile foundation construction, the strength of the pile structure can be enhanced by adopting a mode of arranging two foundation pit guard piles in part of construction, so that deformation of the foundation pit guard piles in the foundation pit excavation process is reduced, the influence of soil subsidence on construction is reduced, but the construction mode greatly increases the construction amount and prolongs the construction period.

Aiming at the related technology, the inventor designs a new construction method of the foundation pit fender post.

Disclosure of Invention

In a first aspect, the present application provides a construction method for a foundation pit fender pile, which adopts the following technical scheme:

the construction method of the foundation pit fender post is characterized by comprising the following steps:

firstly, constructing a foundation pit guard pile, arranging a pile body of the foundation pit guard pile in a soil body, arranging a pre-pulling hole along the length direction of the pile body, and penetrating a pre-pulling rope in the pre-pulling hole, wherein the lower end of the pre-pulling rope is fixedly arranged with the pile body;

step two: the pile body is applied with prestress, the upper end of the pretensioned rope is pulled, and after the pretensioned rope is pulled to a set position, the upper end of the pretensioned rope is fixed to keep the prestress of the pretensioned rope.

Through adopting above-mentioned technical scheme, set up the rope of pretensioning in the pile body of foundation ditch fender pile, after the foundation ditch excavation is accomplished, the pile body receives the unilateral pressure of soil body side, the pile body can produce the trend of crooked to the foundation ditch side, the crooked trend of pile body can produce the pulling force of elongating the rope to the rope of pretensioning in the pile body, the rope of pretensioning that has pretensioning can effectually offset effort under the condition that does not take place deformation by oneself, and then play the holding effect to the shape of pile body, prevent the pile body deformation. After the pile body construction of the foundation pit guard pile is completed, pre-stressing is applied to the pile body, and soil body stabilizes the pile body structure, so that the integral structure of the pile body can be prevented from being damaged in the pre-stressing process.

Optionally, the foundation pit fender pile in the first step is a bored pile;

the first step comprises the following steps: s11, forming holes in the guard piles, and excavating pouring holes in the ground; s12, installing an embedded part, and lowering a reinforcement cage, a pre-tensioning rope and a pre-tensioning pipeline forming a pre-tensioning hole into the pouring hole, wherein the pre-tensioning rope is arranged in the pre-tensioning pipeline in a penetrating manner, and the lower end of the pre-tensioning rope is fixedly provided with a bottom end limiting part; s13, pouring the pile body, pouring concrete slurry into the pouring hole, and waiting for the pile body to solidify.

By adopting the technical scheme, in the process of carrying out the construction of the bored pile, the pre-tightening pipeline is pre-embedded into the bored hole in advance so as to form a pre-pulling hole in the pile body. Simultaneously, the pre-tensioning rope is arranged in the pre-tensioning pipeline in a penetrating mode in advance, and the lower end of the pre-tensioning rope is fixed at the lower end of the pile body through the bottom end limiting piece to form fixation. Under the condition of not interfering with the construction of the pile body of the bored pile, a pre-pulling hole is reserved, a pre-pulling rope is fixed, and the construction of the bored pile and the application of pre-stress are facilitated.

Optionally, S12 further comprises lowering a grouting pipe into the grouting hole, wherein the lower end of the grouting pipe is communicated with the lower end of the pre-tightening pipe;

the second step comprises: s21, drawing the pre-tensioning rope, after the concrete pile body is solidified, drawing the upper end of the pre-tensioning rope by using a hollow jack, fixing the upper end of the pre-tensioning rope after the pre-tensioning rope is drawn to a set position, and disassembling the jack; s22, filling the gaps, namely filling high-strength slurry from the grouting pipe, and stopping grouting when the high-strength slurry emerges from the upper end of the pre-tightening pipeline.

By adopting the technical scheme, the gap in the pile body is filled after construction is finished, so that the structural strength of the pile body is ensured. The grouting pipe is used for grouting from the bottom of the pre-tensioning hole, and the top of the pre-tensioning hole is used as an exhaust hole, so that the grouting compactness is guaranteed, and a hollowing structure in the pile body is avoided.

Optionally, the foundation pit guard pile in the first step is a precast pile, and the pre-tensioning hole is arranged in the pile body of the precast pile in a penetrating manner along the length direction;

the first step comprises the following steps: s11, customizing precast piles; s12, installing a pre-tensioning rope, penetrating the pre-tensioning rope into a pre-tensioning hole of the precast pile, and fixing the end part of the pre-tensioning rope and the lower end of the precast pile together; s13, installing the precast pile, and nailing the precast pile into the ground.

Through adopting above-mentioned technical scheme, when using the precast pile to carry out the construction of foundation ditch fender pile, predetermine the broaching in the pile body through the precast pile, for the installation of stay cord provides the space in advance, can not excessively increase the preparation degree of difficulty of precast pile.

Optionally, a grouting hole is further formed in the precast pile, and the lower end of the grouting hole is communicated with the lower end of the pre-tensioning hole; the upper end of the grouting hole penetrates through the precast pile;

the second step comprises: s21, drawing the pre-tensioning rope, after the pile body is nailed into the soil body, drawing the upper end of the pre-tensioning rope by using a hollow jack, fixing the upper end of the pre-tensioning rope after the pre-tensioning rope is drawn to a set position, and disassembling the jack; s22, filling the gaps, namely filling high-strength slurry from the grouting holes, and stopping grouting when the high-strength slurry emerges from the upper ends of the pre-pulling holes.

By adopting the technical scheme, the gap in the precast pile body is filled after construction is finished, so that the structural strength of the pile body is ensured. The grouting pipe is used for grouting from the bottom of the pre-tensioning hole, and the top of the pre-tensioning hole is used as an exhaust hole, so that the grouting compactness is guaranteed, and a hollowing structure in the pile body is avoided.

Optionally, the precast pile comprises a pile body and a pointed pile head, wherein the pointed pile head comprises a pile head body and an enlarged shell coated on the outer side of the pile head body; a material pressing hole communicated with the grouting hole and the inner cavity of the enlarged casing is preset in the pile head;

the second step also comprises the following steps: s23, grouting material is pressed, the upper end of the pre-pulling hole is plugged by a plug piece, and grouting pressure is controlled to be 1-40MPa and gradually increased; after the pressure reaches 40MPa, the pressure is maintained for 1-5 days.

Through adopting above-mentioned technical scheme, with grout hole, prestretch the hole and fill up the back, shutoff prestretch the hole top, continue the mode of grout, with thick liquids indentation enlarge between shell and the pile head body to utilize the liquid thick liquids of high pressure to prop the enlarged shell big, form the enlarged head in the bottom of foundation ditch fender post, increase the bottom of foundation ditch fender post and the area of contact of soil body, further strengthen the pile body to the fixed action of soil body, better prevention soil body lower limit.

Optionally, the grouting holes and the pre-tensioning holes penetrate through the pile body of the precast pile; a feeding hole communicated with the bottom end of the grouting hole and a discharging hole communicated with the bottom end of the pre-pulling hole are also arranged in the pointed pile head, and the feeding hole and the discharging hole are both communicated with the pressing hole; the grouting holes and the pre-stretching holes are communicated with the bottom through the feeding holes, the pressing holes and the discharging holes.

Through adopting above-mentioned technical scheme, utilize the bottom intercommunication of the feed port in the pile head body, press the material hole, the discharge port will grout the hole with prestretch the hole, grout pipe is earlier to this internal feed port of pile head, press the material hole, the discharge port is grouted, this internal air of pile head can be discharged through the discharge port, this internal retention hollowing of effective prevention pile head, guarantee structural strength.

Optionally, the precast pile is a concrete-filled steel tube precast pile, the pile body comprises a steel tube and a concrete core arranged in the steel tube, and an inserting cavity formed by unfilled concrete core is reserved at the lower end of the steel tube; the pile head is characterized in that one end of the pile head body, which is close to the pile body, is provided with a plug-in part, the edge of the expansion shell is coated on the side wall of the plug-in part, and the plug-in part of the expansion shell is coated to be in plug-in fit with the plug-in cavity.

Through adopting above-mentioned technical scheme, reserve the grafting chamber in the pile body bottom, set up grafting portion on the tip pile head, made things convenient for the combination of pile body and tip pile head, the steel pipe cooperation pile head body of pile body carries out the centre gripping to the border of enlarging the shell fixed simultaneously, has saved to enlarge the shell border and has carried out special fixed.

Optionally, the upper end of the pre-tensioned rope is fixed with the end part of the pile body through a tensioning end anchor; and the anchor backing plate of the stretching end anchor is penetrated and provided with a slurry hole communicated with the pre-stretching hole.

By adopting the technical scheme, the existing tension end anchorage is used as an end fixing part of the pretension rope, the materials are convenient to obtain, and the construction scheme is mature; the existing anchor backing plate is provided with a tensioning end anchorage device with grouting holes, and the grouting holes can be directly used as the material holes.

Optionally, the pretension Kong Pianxiang foundation pit side is arranged.

Through adopting above-mentioned technical scheme, when precast pile's pile body takes place to warp, the pile body that is close to the foundation ditch side is length deformation biggest, therefore the pile body deformation trend that is close to the foundation ditch side is more obvious, will prestretch Kong Pianxiang foundation ditch side setting, prestretches the rope and can more obvious receive the pulling force effect of pile body, prestretches the downthehole prestretches the rope and can more effectively offset the load that the pile body received, better prevention pile body takes place to warp.

In summary, the present application includes at least one of the following beneficial technical effects:

1. according to the construction method for the foundation pit guard pile, after the pile body construction of the foundation pit guard pile is completed, the pre-tensioning rope is used for applying pre-stress to the pile body along the length direction of the pile body, so that the deformation trend of the pile body is limited, the soil body after excavation of the foundation pit is prevented from being pressed to deform, pre-tensioning holes and pre-tensioning ropes are reserved in the pile body in advance, the pre-tensioning ropes are pulled after the pile body is arranged in the soil body, pre-stressing is applied to the precast pile, the pile body structure is surrounded by the soil body, and pre-stressing is applied, so that the pre-tensioning is prevented from affecting the strength of the pile body or affecting the transportation of the precast pile in advance under the condition of using the precast pile;

2. the grouting pipe or the grouting hole is arranged, after the pre-tensioning rope is stretched and fixed, the structure of the pre-tensioning hole is grouted and filled from the bottom, the top of the pre-tensioning hole is used as an exhaust port, the hole structure in the foundation pit guard pile is effectively ensured to be filled tightly, the empty drum structure is prevented from being generated, and the strength of the foundation pit guard pile is ensured;

3. when the precast pile is used for the foundation pit guard pile, the pointed pile head is arranged at the bottom of the pile body, the pile head body with the enlarged shell can be used for enlarging the enlarged shell by utilizing high-pressure slurry in the process of pouring holes, the enlarged head is formed at the bottom of the foundation pit guard pile, the bearing capacity of the bottom of the foundation pit guard pile is improved, and the blocking effect of the foundation pit guard pile on soil is further optimized.

Drawings

FIG. 1 is a schematic diagram of foundation pit fender post stress in the related art of the present application;

FIG. 2 is a schematic view of construction structure of example 1 of the present application;

FIG. 3 is an enlarged view of area A of FIG. 2;

fig. 4 is a schematic view of a precast pile structure according to embodiment 2 of the present application;

FIG. 5 is an enlarged view of region B of FIG. 4;

fig. 6 is a schematic view showing an expanded state of the enlarged case according to embodiment 2 of the present application.

Reference numerals: 1. a foundation pit; 2. foundation pit guard piles; 3. soil mass; 4. pouring holes; 51. a reinforcement cage; 52. a bottom end limiting member; 521. a communication hole; 53. pretensioning the rope; 54. pre-tightening the pipeline; 541. pre-pulling holes; 55. grouting pipes; 551. grouting holes; 6. stretching an end anchor; 61. an anchor backing plate; 611. a slurry hole; 62. spiral ribs; 63. an anchor ring; 64. a clamping piece; 71. a steel pipe; 711. a plug cavity; 72. a concrete core; 73. a concrete surface layer; 81. a pile head body; 811. a plug-in part; 812. a feed hole; 813. a pressing hole; 814. a discharge hole; 82. enlarging the shell.

Detailed Description

The application discloses a construction method of foundation pit fender piles.

Example 1

Referring to fig. 2 and 3, the foundation pit fender pile is a bored pile.

A foundation pit fender pile construction method comprises the following steps:

and step one, constructing foundation pit fender piles.

S11, forming holes in the fender posts. The filling holes 4 are excavated on the ground by using a rotary pile-digger and a punching pile-digger.

S12, installing embedded parts. A reinforcement cage 51, a bottom end limiting piece 52, a pre-tensioning rope 53, a pre-tensioning pipeline 54 and a grouting pipe 55 are put into the pouring hole 4; the pre-tensioned rope 53 is a steel strand, and the bottom end limiting piece 52 is an iron plate welded and fixed at the lower end of the pre-tensioned rope 53; the pre-tensioning rope 53 is arranged in the pre-tensioning pipeline 54 in a penetrating way, and the bottom end limiting piece 52 is clamped at the end part of the lower end of the pre-tensioning pipeline 54; the grouting pipe 55 and the pre-tightening pipe 54 are both stainless steel pipes 71, and the lower end of the grouting pipe 55 is closed and communicated with the lower end of the pre-tightening pipe 54 through a pipe; the pre-tightening pipeline 54 is arranged in an offset manner towards the side of the foundation pit to be excavated; the upper ends of the pre-tightening pipe 54 and the grouting pipe 55 are fixed with the reinforcement cage 51 through scrap iron strips on the construction site, and the scrap iron strips are welded and fixed with other components. An anchor backing plate 61 and a spiral rib 62 of the stretching end anchor 6 are arranged at the upper end of the pre-stretching rope 53, and a slurry hole 611 communicated with the pre-tightening pipeline 54 is arranged on the anchor backing plate 61 of the stretching end anchor 6.

S13, pile body pouring. Pouring concrete slurry into the pouring hole 4, and waiting for the pile body to solidify; pre-tensioned duct 54 forms a pre-tensioned aperture 541 in the shaft and grout tube 55 forms a grout aperture 551 in the shaft.

Step two: the pile body is prestressed.

S21, pulling the pretensioned rope 53. After the concrete pile body is solidified, the anchor ring 63 and the clamping piece 64 of the tensioning end anchor 6 are installed, the upper end of the pre-tensioning rope 53 is pulled by using the hollow jack, and the hollow jack is disassembled after the pre-tensioning rope 53 is pulled to a set position.

S22, filling gaps. High-strength slurry is poured from a grouting pipe 55, and epoxy resin slurry is adopted in the embodiment; grouting is stopped when high-strength slurry is discharged from the slurry holes 611 of the anchor pad 61 of the tension end anchor 6.

The implementation principle of the embodiment 1 is as follows: after pile body of the bored pile is poured, pretension force is applied to the pretension rope 53 by pulling the pretension rope 53, and two ends of the pretension rope 53 are fixed with the end parts of the pile body through the bottom end limiting piece 52 and the tensioning end anchor 6; when the pile body is pressed by a soil body on one side, the pile body can generate a bending trend, the bending of the pile body can pull the side length of the pre-tensioning rope 53 in the pile body, and the pre-tensioning rope 53 with the pre-tensioning force can provide enough reaction force to counteract the pulling force on the premise of not deforming the pile body, so that the bending of the pile body is limited, and the blocking effect of the foundation pit guard pile on the soil body is ensured; the pre-tightening pipeline 54 and the pre-tightening ropes 53 are arranged towards the foundation pit side, and the pile body is bent towards the foundation pit side, so that the deformation amount of the part of the pile body close to the foundation pit side is larger, the deformation trend is more obvious, and the pre-tightening ropes 53 can effectively prevent the pile body from deforming.

Example 2

Referring to fig. 4 and 5, the foundation pit guard piles are steel pipe 71 concrete precast piles and square piles.

A foundation pit fender pile construction method comprises the following steps:

and step one, constructing foundation pit fender piles.

S11, customizing the precast pile. The precast pile comprises a pile body and a pointed pile head. The pile body comprises a rectangular steel pipe 71, a concrete core 72 arranged in the steel pipe 71 and a concrete surface layer 73 arranged outside the steel pipe 71; the concrete core 72 is embedded with a pre-tightening pipeline 54 and a grouting pipe 55, and the pre-tightening pipeline 54 and the grouting pipe 55 penetrate through the whole concrete core 72 and form a pre-tightening hole 541 and a grouting hole 551 penetrating through the concrete core 72; the lower end 10-15cm of the steel tube 71 is not filled with the concrete core 72 and forms a socket 711. The pinnacle pile head comprises a pile head body 81 and an enlarged casing 82 coated on the outer side of the pile head body 81; the pile head body 81 is in a quadrangular pyramid shape as a whole, a connecting section of the pile head body 81 and the pile body is provided with a plug-in part 811, the edge of the enlarged shell 82 is coated on the side wall of the plug-in part 811, and the plug-in part 811 coated on the enlarged shell 82 is in plug-in fit with the plug-in cavity 711; the tip pile head is internally provided with a feed hole 812 corresponding to the bottom end pipe orifice of the grouting pipe 55, a discharge hole 814 corresponding to the bottom end pipe orifice of the pre-tightening pipe 54, and a pressing hole 813 communicated with the feed hole 812 and the discharge hole 814, wherein the pressing hole 813 penetrates through the side wall of the pile head body 81 and is communicated to the inner cavity of the enlarged casing 82. The upper end of the pre-tightening pipeline 54 is provided with an anchor backing plate 61 and a spiral rib 62 of the tensioning end anchor 6, the anchor backing plate 61 and the spiral rib 62 are embedded in the concrete core 72, and the anchor backing plate 61 of the tensioning end anchor 6 is provided with a slurry hole 611 communicated with the pre-tightening pipeline 54.

S12, the pretensioned rope 53 is installed. One end of the pretension rope 53 is welded and fixed with a metal plate as a bottom end limiting piece 52, the pretension rope 53 is inserted into the pretension hole 541 from one side of the plugging cavity 711, and the limiting plate is clamped at the end part of the pretension pipeline 54; the plate body of the bottom end limiting piece 52 is provided with a communication hole 521 in a penetrating way to communicate with a pre-pulling hole 541, and the communication hole 521 on the bottom end limiting piece 52 corresponds to the position of the discharging hole 814 so as to communicate the two; the pinnacle pile head is inserted and fixed in the insertion cavity 711 at the lower end of the steel pipe 71.

S13, installing precast piles. The utility pile driver drives the precast pile into the ground.

Step two: the pile body is prestressed.

S21, pulling the pretensioned rope 53. An anchor ring 63 and a clamping piece 64 of the stretching end anchor 6 are arranged at the upper end of the pre-stretching rope 53, the upper end of the pre-stretching rope 53 is pulled by using a hollow jack, and the hollow jack is disassembled after the pre-stretching rope 53 is pulled to a set position.

S22, filling gaps. High-strength slurry is poured from the upper end of the grouting hole 551, and epoxy resin slurry is adopted in the embodiment; grouting is stopped when high-strength slurry is discharged from the slurry holes 611 of the anchor pad 61 of the tension end anchor 6.

S23, grouting material is pressed. The pretension hole 541 of the anchor backing plate 61 of the tension end anchor 6 is blocked by a plug, and a heavy object is placed above the pretension hole to ensure the tight blocking. Grouting into the grouting holes 4 again, wherein the grouting pressure is controlled to be 1-40MPa, and the pressure is gradually increased; stopping pressurizing after the grouting pressure reaches 40MPa, maintaining the pressure for 1-5 days, and preventing the slurry in the grouting holes 4 from being pressed out.

Referring to fig. 6, by grouting the slurry, the expansion shell 82 is spread, and an expansion head is formed at the bottom of the foundation pit fender post, so that the bearing capacity and stability of the whole foundation pit fender post are enhanced.

The implementation principle of the embodiment 2 is as follows: by reserving the pre-tensioning hole 541 in the pile body of the precast pile, the pre-tensioned rope 53 is inserted into the precast pile before the precast pile is installed, and tensioning is performed after the precast pile is driven into the ground to apply a pre-stress. The pile head body 81 coated with the expansion shell 82 is arranged, when the grouting holes 551 and the pre-tensioning holes 541 are filled with high-strength slurry, the expansion shell 82 in the soil body is expanded to form expansion heads, the bearing capacity and stability of the bottom of the foundation pit fender pile are enhanced, and the effect of the foundation pit fender pile on blocking the soil body is further optimized.

The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims (10)

1. The construction method of the foundation pit fender post is characterized by comprising the following steps:

firstly, constructing a foundation pit guard pile, arranging a pile body of the foundation pit guard pile in a soil body, arranging a pre-pulling hole (541) along the length direction of the pile body, and penetrating a pre-pulling rope (53) in the pre-pulling hole (541), wherein the lower end of the pre-pulling rope (53) is fixedly arranged with the pile body;

step two: the pile body is pre-stressed, the upper end of the pre-stretching rope (53) is pulled, and after the pre-stretching rope (53) is pulled to a set position, the upper end of the pre-stretching rope (53) is fixed to keep the pre-stressing of the pre-stretching rope (53).

2. The foundation pit fender pile construction method of claim 1, wherein: the foundation pit guard pile in the first step is a bored pile;

the first step comprises the following steps: s11, forming holes in the guard piles, and excavating pouring holes (4) on the ground; s12, installing an embedded part, lowering a reinforcement cage (51), a pre-tensioning rope (53) and a pre-tensioning pipeline (54) forming a pre-tensioning hole (541) into a pouring hole (4), wherein the pre-tensioning rope (53) is penetrated into the pre-tensioning pipeline (54), and a bottom end limiting part (52) is fixed at the lower end of the pre-tensioning rope (53); s13, pouring the pile body, pouring concrete slurry into the pouring hole (4), and waiting for the pile body to solidify.

3. The foundation pit fender pile construction method of claim 2, wherein: s12 further comprises the step of lowering a grouting pipe (55) into the pouring hole (4), wherein the lower end of the grouting pipe (55) is communicated with the lower end of the pre-tightening pipeline (54);

the second step comprises: s21, drawing the pre-tensioning rope (53), after the concrete pile body is solidified, drawing the upper end of the pre-tensioning rope (53) by using a hollow jack, fixing the upper end of the pre-tensioning rope (53) after the pre-tensioning rope (53) is drawn to a set position, and disassembling the jack; s22, filling the gaps, namely filling high-strength slurry from a grouting pipe (55), and stopping grouting when the high-strength slurry is emitted from the upper end of the pre-tightening pipeline (54).

4. The foundation pit fender pile construction method of claim 1, wherein: the foundation pit guard pile in the first step is a precast pile, and the pre-tensioning hole (541) is arranged in the pile body of the precast pile in a penetrating manner along the length direction;

the first step comprises the following steps: s11, customizing precast piles; s12, installing a pre-tensioning rope (53), penetrating the pre-tensioning rope (53) into a pre-tensioning hole (541) of the precast pile, and fixing the end part of the pre-tensioning rope (53) and the lower end of the precast pile together; s13, the step of,

and installing the precast pile, and nailing the precast pile into the ground.

5. The foundation pit fender pile construction method of claim 4, wherein: a grouting hole (551) is also formed in the precast pile, and the lower end of the grouting hole (551) is communicated with the lower end of the pre-tensioning hole (541); the upper end of the grouting hole (551) penetrates through the precast pile;

the second step comprises: s21, drawing a pre-tensioning rope (53), after a pile body is nailed into a soil body, drawing the upper end of the pre-tensioning rope (53) by using a hollow jack, fixing the upper end of the pre-tensioning rope (53) after the pre-tensioning rope (53) is drawn to a set position, and disassembling the jack; s22, filling the gaps, namely filling high-strength slurry from the grouting holes (551), and stopping grouting when the high-strength slurry is emitted from the upper ends of the pre-tensioning holes (541).

6. The foundation pit fender pile construction method of claim 5, wherein: the precast pile comprises a pile body and a pointed pile head, wherein the pointed pile head comprises a pile head body (81) and an enlarged shell (82) coated on the outer side of the pile head body (81); a material pressing hole (813) communicated with the grouting hole (551) and the inner cavity of the enlarged casing (82) is preset in the pile head body (81);

the second step also comprises the following steps: s23, grouting material is pressed, the upper end of the pre-pulling hole (541) is plugged by a plug piece, and grouting pressure is controlled to be 1-40MPa and gradually increased; after the pressure reaches 40MPa, the pressure is maintained for 1-5 days.

7. The foundation pit fender pile construction method of claim 6, wherein: the grouting holes (551) and the pre-tensioning holes (541) penetrate through the pile body of the precast pile; a feeding hole (812) communicated with the bottom end of the grouting hole (551) and a discharging hole (814) communicated with the bottom end of the pre-pulling hole (541) are further formed in the pointed pile head, and the feeding hole (812) and the discharging hole (814) are both communicated with the pressing hole (813); the grouting holes (551) and the pre-stretching holes (541) are communicated with the bottom through the feeding holes (812), the pressing holes (813) and the discharging holes (814).

8. The foundation pit fender pile construction method of claim 7, wherein: the precast pile is a steel pipe (71) concrete precast pile, the pile body comprises a steel pipe (71) and a concrete core (72) arranged in the steel pipe (71), and an inserting cavity (711) which is not filled with the concrete core (72) is reserved at the lower end of the steel pipe (71); the pile head comprises a pile head body (81), wherein a plug-in portion (811) is arranged at one end, close to the pile body, of the pile head body, the edge of an enlarged shell (82) is coated on the side wall of the plug-in portion (811), and the plug-in portion (811) of the enlarged shell (82) is coated to be in plug-in fit with a plug-in cavity (711).

9. The foundation pit fender pile construction method of claim 1, wherein: the upper end of the pre-tensioning rope (53) is fixed with the end part of the pile body through a tensioning end anchor (6); slurry holes (611) communicated with the pre-pulling holes (541) are formed in the anchor backing plate (61) of the tensioning end anchor device (6) in a penetrating mode.

10. The foundation pit fender pile construction method of claim 1, wherein: the pre-tensioning holes (541) are arranged at the side of the foundation pit.

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